Recent development in wireless network technology has led to the introduction of new wireless communication networks with ever increasing data bandwidths and peak data rates. As a consequence, a number of new more or less bandwidth intensive applications have been introduced as services in the wireless network, such as audio and video streaming services, VoIP (Voice-over-IP), online multiplayer computer games and so on. These new services co-exist with standard services, such as interactive and conversational data traffic. With some services, data throughput is the important parameter, while other services require low data transmission delay or latency for maximum user satisfaction.
According to the 3GPP (Third Generation Partnership Project) standard for HSDPA (High Speed Downlink Packet Access), a mobile terminal (UE—User Equipment) shall report a perceived radio channel quality over the air interface to a UTRAN (Universal Terrestrial Radio Access Network). This is reported by means of a Channel Quality Indicator (CQI) information element contained in an associated uplink signaling channel HS-DPCCH (High Speed Downlink Physical Control Channel). The CQI value reported by the UE reflects the UE's perceived channel quality and indicates the UE's capability to decode the user data sent on the HS-DSCH (High Speed Downlink Shared Channel) and is used by the UTRAN for UE scheduling, power management and transport block (TB) selection. The standard mandates that the UE CQI report should target a data error rate of 10%. In the example case of a HSPDA-network, this data error rate is expressed as a HARQ BLER (Hybrid Automatic Repeat Request Block Error Rate) parameter. These principles are illustrated in FIG. 1.
Typically, HS-DSCH systems target a certain BLER value in order to maximize the cell throughput and it is common practice in networks today to aim at a HARQ BLER of 10%.
However, the HSDPA-standard does not rule out the possibility to target other values of the HARQ BLER-parameter than 10%.
While such a BLER target has advantages concerning cell throughput it also has the disadvantage that there is a 10% chance that there will be a retransmission on the HS-DSCH leading to a reduction in the user perceived throughput and data transmission delays. Especially the latter factor may lead to deterioration in the user perceived quality of streaming audio and/or video services, online gaming, VoIP and voice conversations. On the other hand a lower HARQ BLER target may lead to a higher probability of a successful data transmission but consumes more power per bit than a transmission targeting a higher BLER value.
Applications such as VoIP, gaming and transmissions of control data from higher layers, such as TCP (Transmission Control Protocol) control data from the network layer place other requirements on the radio channel than simply maximum throughput, such as, for example, low latency.
Thus, the aim of the present invention is to solve at least some of the problems associated with known technology.